Multilayer container

ABSTRACT

A multilayer container for dispensing product that includes a relatively rigid outer body and a relatively flexible inner liner for holding product to be dispensed. The relatively rigid outer body includes, and preferably consists essentially of, an outer layer of virgin polyethylene such as HDPE, and an inner thicker layer that includes polyethylene regrind. The relatively flexible inner liner includes, and preferably consists essentially of, an outer delamination layer adjacent to the inner layer of the body and composed of nylon, nylon blends or EVOH, an inner layer of polyethylene such as LLDPE, and an adhesive securing the inner and outer layers of the liner. The relatively thin outer HDPE layer on the plastic body provides desired appearance, while the thicker inner layer provides structural rigidity using reground plastics. The nylon, nylon blend or EVOH outer liner layer provides improved barrier properties against migration of water, gases and flavorants, while the inner layer of LLDPE provides primarily enhanced flexibility and freedom from cracking, as well as additional barrier moisture qualities.

[0001] This application is a continuation of application Ser. No.09/287,934 filed Apr. 7, 1999.

[0002] The present invention is directed to multilayer containers, andmore particularly to containers that comprise a relatively rigid outerplastic body and a relatively flexible inner plastic liner.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] It has heretofore been proposed to provide a container in theform of a relatively rigid outer plastic body and a relatively flexibleinner plastic liner. The container body has a dispensing opening at oneend and an atmospheric vent at the opposing end. The inner liner iscoupled to the dispensing opening. When containers of this type areemployed in conjunction with pump or spray dispensers, for example, theinner liner delaminates from and collapses within the outer plastic bodyas product is dispensed, with air entering through the atmospheric ventbetween the outer body and the collapsing liner.

[0004] As the liner collapses when the product is dispensed, stresscracks or pinholes can appear along the folds and creases of the liner,causing product leakage and loss. It is therefore a general object ofthe present invention to provide a multilayer container of the subjecttype in which the liner readily delaminates from the relatively rigidplastic body as product is dispensed, in which the liner provides notonly improved barrier properties but also improved flexibility forelimination of stress cracks and pinholes. Another object of the presentinvention is to provide a container of the subject type that exhibitsreduced product weight loss as compared with structures in the priorart. Yet another object of the invention is to provide a multilayercontainer of the described character that employs plastic regrind in thecontainer package to promote recycling of moils and scrap.

[0005] A multilayer container for dispensing product includes arelatively rigid outer plastic body and a relatively flexible innerplastic liner for holding product to be dispensed. In accordance withone aspect of the present invention, the relatively rigid outer bodyincludes, and preferably consists essentially of, an outer layer ofvirgin polyethylene such as HDPE, and an inner thicker layer thatincludes process regrind. In accordance with another aspect of theinvention, the relatively flexible inner liner includes, and preferablyconsists essentially of, an outer delamination layer adjacent to theinner layer of the body and composed of nylon, nylon blends or EVOH, aninner layer of polyethylene such as LLDPE, and an adhesive securing theinner and outer layers of the liner. The relatively thin outer HDPElayer on the plastic body provides desired appearance, while the thickerinner layer provides structural rigidity using reground plastics. Thenylon, nylon blend or EVOH outer liner layer provides improved barrierproperties against migration of water, gases and flavorants, while theinner layer of LLDPE provides enhanced flexibility, freedom fromcracking and additional barrier properties.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention, together with additional objects, features andadvantages thereof, will be best understood from the followingdescription, the appended claims and the accompanying drawings in which:

[0007]FIG. 1 is an elevational view of a multilayer container inaccordance with a presently preferred embodiment of the invention;

[0008]FIG. 2 is a top plan view of the container illustrated in FIG. 1;

[0009]FIG. 3 is a bottom plan view the container illustrated in FIG. 1;

[0010]FIG. 4 is a sectional view taken substantially along the line 4-4in FIG. 2;

[0011]FIG. 5 is an enlarged fragmentary sectional view of the portion ofFIG. 4 within the circle 5;

[0012]FIG. 6 is an enlarged fragmentary sectional view of the portion ofFIG. 4 within the circle 6; and

[0013]FIG. 6A illustrates delamination of the structure illustrated inFIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0014] The drawings illustrate a container 10 in accordance with apresently preferred embodiment of the invention as comprising arelatively rigid outer plastic body 12 and a relatively flexible innerplastic liner 14. Body 12 has a dispensing opening 16 surrounded by acontainer finish 18 at one end of the body, and an atmospheric vent 20disposed at the opposing end of the body. Inner liner 14 communicateswith opening 16 at finish 18 of container body 12, and is otherwiseclosed to prevent ingress of air. Vent 20 comprises a slot that extendsdiametrically across the lower end or bottom of container 12, beingformed by the tearing away of the tail of the molded plastic body whenthe molds start to open after the bottle has been made.

[0015] To the extent thus far described, container 10 is similar to thatdisclosed in U.S. application Ser. No. 08/807,944 assigned to theassignee hereof and incorporated herein by reference for purposes ofbackground. When a pump or spray dispenser is secured to containerfinish 18, product within liner 14 can be dispensed by operation of thepump or spray dispenser. As product is dispensed, negative pressurewithin liner 14 causes liner 14 to separate from container body 12.Atmospheric air enters vent 20 to permit such separation. Thus, theliner collapses as the product is dispensed, while body 12 retains itsoriginal configuration due to its inherent rigidity as well asseparation of the liner from the inner surface of the body. Container 10preferably is manufactured by a co-extrusion and blow molding process ofthe type illustrated in U.S. Pat. Nos. 3,781,395, 3,767,747 and3,978,184.

[0016] In accordance with the present invention, relatively rigid outerplastic body 12 includes, and preferably consists essentially of, a thinouter layer 22 and a thicker inner layer 24. Likewise, liner 14 inaccordance with the present invention includes, and preferably consistsessentially of, an outer layer 26 and an inner layer 28. These layersare formed in an otherwise conventional co-extrusion and blow-moldingoperation, such as those disclosed in the U.S. patents cited immediatelyabove. Outer layer 22 of container body 12 preferably consists ofhigh-density polyethylene (HDPE) and has a thickness not greater than0.004 inches. Inner layer 24 of container body 12 preferably comprises70% virgin HDPE and 30% process regrind (i.e., regrind of HDPE, LLDPE,nylon, nylon blend or EVOH, and previous regrind from process spoils andscrap). Inner layer 24 preferably has a thickness in the range of 0.006to 0.020 inches. Thus, outer layer 22 provides the desired appearance tothe overall container, while inner layer 24 provides structural rigidityusing regrind materials.

[0017] Outer layer 26 of liner 14 preferably is of composition selectedfrom the group consisting of nylon, nylon blends and EVOH, having athickness in the range of 0.002 to 0.004 inches. Inner layer 28preferably comprises linear low density polyethylene (LLDPE), having athickness in the preferred range of 0.002 to 0.004 inches. Liner 14 alsoincludes an adhesive, which preferably is blended with the LLDPEmaterial of inner layer 28 in a ratio of 80% virgin LLDPE to 20%adhesive. This adhesive secures inner layer 28 to outer layer 26.Alternatively, the adhesive may be provided in the form of a thin layerbetween layers 26,28, which would use less adhesive material and preventcontact between the adhesive material and the product contained withinliner 14. The nylon, nylon blend or EVOH composition of outer layer 26provides ready delamination of liner 14 from container body 12, and alsoprovides a barrier against loss of product, gas migration or loss ofproduct flavorants. The LLDPE material of inner liner 28 provides highflexibility while resisting formation of stress cracks and pinholes asliner 14 collapses.

[0018] Tests have been conducted on containers in accordance the presentinvention using a crystalized nylon material in layer 26 and a liquidsoap product. Projected annual product loss was 0.1% at 73° F., 1.3% at100° F. and 2.5% at 120° F.

[0019] It will therefore be recognized that a multilayer container hasbeen provided in accordance with the present invention, which fullysatisfies all of the objects and aims previously set forth. Thetwo-layer construction of the inner liner or bag 14 provides improvedbarrier properties while eliminating stress cracks and pinholes. Thetwo-layer construction of the liner 14 also provides improvedflexibility and strength. The overall container exhibits a reducedannual product weight loss. No pre-delamination is required between theliner and container body when product is dispensed. Process regrind isrecycled into the package. The process does not need to use nitrogen assupport air.

1. A multilayer container for dispensing product, which includes: arelatively rigid outer plastic body and a relatively flexible innerplastic liner for holding product to be dispensed, said relatively rigidouter body having a dispensing opening at one end and an atmosphericvent, said relatively flexible inner liner opening at said dispensingopening, said outer body comprising a radially outer layer ofpolyethylene, and a radially inner layer that is thicker than said outerlayer and includes process regrind, said relatively flexible inner linerincluding a radially inner layer of polyethylene, and a radially outerlayer of barrier material adjacent to said inner layer of said body andnot adhered to said inner layer of said body, said outer layer ofbarrier material being selected from the group consisting of nylon,nylon blends and EVOH, said liner being adjacent to an easily separablefrom said inner layer of said body.
 2. The container set forth in claim1 wherein said inner liner includes an adhesive bonding said inner layerof said liner to said outer layer of said liner.
 3. The container setforth in claim 2 wherein said adhesive is blended with said polyethyleneof said inner layer of said liner.
 4. The container set forth in claim 2wherein said adhesive is in a separate layer between said inner andouter layers of said liner.
 5. The container set forth in claim 1wherein said inner layer of said liner comprises LLDPE.
 6. The containerset forth in claim 1 wherein said inner and outer layers of said linereach have a thickness in the range of 0.006 to 0.020 inches.
 7. Thecontainer set forth in claim 1 wherein said outer layer of said body isvirgin HDPE, and said inner layer of said body is comprised of virginHDPE and process regrind.
 8. The container set forth in claim 7 whereinsaid inner layer of said body is 70% virgin HDPE and 30% processregrind.
 9. The container set forth in claim 7 wherein said outer layerof said body is not more than 0.004 inches thick, and said inner layerof said body is in the range of 0.010 to 0.020 inches thick.
 10. Amultilayer container for dispensing product, which includes: an outerplastic body and an inner plastic liner for holding product to bedispensed, said outer plastic body including a radially outer layer ofvirgin polyethylene, and a radially inner layer of polyethylene andprocess regrind, said inner plastic liner being more flexible and lessrigid than said outer plastic body, said relatively rigid outer body hasa dispensing opening at one end and an atmospheric vent, and saidrelatively flexible inner liner opening at said dispensing opening, saidinner liner consisting essentially of a radially outer layer of barriermaterial selected from the group consisting of nylon, nylon blends andEVOH, a radially inner layer of polyethylene, and an adhesive securingsaid inner and outer layers of said liner to each other, said outerlayer of said liner being adjacent and not adhered to an inner surfaceof said outer plastic body.
 11. The container set forth in claim 10wherein said outer plastic body consists essentially of a radially outerlayer of virgin polyethylene and a radially inner layer of virginpolyethylene and process regrind, and wherein said radially inner layerof said inner line is of LLDPE.
 12. The container set forth in claim 11wherein said radially inner layer of said outer plastic body is thickerthan said radially outer layer of said outer plastic body.
 13. Thecontainer set forth in claim 11 wherein said inner layer of said body isat least 70% virgin HDPE and not more than 30% regrind.
 14. Thecontainer set forth in claim 10 wherein said adhesive is blended withsaid inner layer of said liner.
 15. The container set forth in claim 10wherein said adhesive is in a separate layer between said inner andouter layers of said liner.
 16. The container set forth in claim 10wherein said inner and outer layers of said liner each have a thicknessin the range of 0.002 to 0.004 inch.
 17. The container set forth inclaim 10 wherein said outer layer of said body is not more than 0.004inches thick, and said inner layer of said body is in the range of 0.010to 0.020 inches thick.
 18. A multilayer container for dispensingproduct, which comprises: a relatively rigid outer plastic body and arelatively flexible inner plastic liner for holding product to bedispensed, said relatively rigid outer body including a radially outerlayer of polyethylene, and a radially inner layer that is thicker thansaid outer layer and includes process regrind, said relatively flexibleinner liner including a radially outer layer of barrier materialadjacent to said inner layer of said body and not adhered to said innerlayer of said body, and a radially inner layer of polyethylene.
 19. Amultilayer container for dispensing product, which comprises: arelatively rigid outer body and a relatively flexible inner liner forholding product to be dispensed, said outer body consisting essentiallyof a radially outer layer of virgin HDPE, and a radially inner layerthicker than said outer layer and consisting essentially of a mixture ofHDPE and process regrind, said inner liner consisting essentially of aradially outer layer selected from the group consisting of nylon, nylonblends and EVOH, a radially inner layer of LLDPE, and an adhesivesecuring said inner and outer layers of said liner, said outer layer ofsaid liner being adjacent to and easily separable from said inner layerof said body.
 20. A multilayer container for dispensing product, whichcomprises: an outer plastic body and an inner plastic liner for holdingproduct to be dispensed, said inner plastic liner being more flexibleand less rigid than said outer plastic body, said inner liner consistingessentially of a radially outer layer of barrier material selected fromthe group consisting of nylon, nylon blends and EVOH, a radially innerlayer of polyethylene, and an adhesive securing said inner and outerlayers of said liner to each other, said outer layer of said liner beingadjacent and not adhered to an inner surface of said outer plastic body.